Bordeaux are due a windfall if the Black Cats secure their safety, a report claims.
Whenever Khazri contributes, Sunderland don't lose. His pass to Jermain Defoe prompted the Black Cats' equaliser against Liverpool in February, while his goal against Manchester United the following week opened the door to a 2-1 win.
And that could cost Sunderland around £3 million in add-ons, according to the Echo, which cites French sources.
The Mirror reports the Black Cats paid Bordeaux £9 million to bring Khazri to the Stadium of Light in January and it is unclear if the remaining £3 million was included in that initial figure.
However, with survival worth approximately 11 times the amount quoted by the Mirror, Sunderland are unlikely to care either way.
A win for the Mackems against Everton in midweek will secure their top-flight status and bring the added bonus of relegating both Norwich City and Newcastle United, their fierce North East rivals.